Throttle body/high idle sometimes

[Ken Dalton]

thanks to this forum for giving me advice on my bad negative battery cable. Replaced that and my first problem was fixed. Now on to problem 2

Edit: I have a 2008 Tahoe LTZ

I had a check engine light come on. Code related to the throttle body. p01021 or something like that.
I bought the ACDelco throttle sensor kit for $30 and also removed the throttle body and carefully cleaned it. I didn't move the plate. I just sprayed, used a toothbrush, sprayed more, installed the new ACdelco piece and installed.

So here's what the tahoe does.
Idle is fine. I give it a little gas and it jumps up to 2000 rpm and stays there then slowly goes down. It eventually goes to the proper idle. When driving it I can feel the vehicle wanting to go fwd because of high idle.

I drove about 15 minutes on and off.
I disconnected positive for 40 minutes.
I drove again
I let idle for 3 minutes
turn off for 1
let idle for 3

Still, same issue. Idles ok, but as soon as I give it gas it jumps way up and stays at 2000 rpm for a bit.

Could the throttle plate be stuck or returning too slow?
do I need to keep driving it to relearn?
should I get a programmer and reset the idle with it?

One guy said to disconnect negative, pump brake 3 times, reconnect battery.
Idle will jump up and car will be fixed. But I got the feeling he meant while car is running! ??

Another guy said spray wd40 on the pivot parts of the plate as its now getting stuck from cleaning.
(this sounds like it could be it)

any advice is appreciated.

 

[Ken Dalton]

I will add my tahoe had a rough idle and it threw that 121 code and the idle is really smooth now and no code or check engine light. Just can't figure out why, when I give it a little throttle, it shoots up to 2000-2500 rpms and very slowly goes down or stays at 2000.

 

[Kip Jennings]

Hello, I see this was posted a year and half ago, I am having the same issues. How did you get the problem solved?

 

[HiHoeSilver]

Hello, I see this was posted a year and half ago, I am having the same issues. How did you get the problem solved?

Did you clean your TB?

 

[Kip Jennings]

Did you clean your TB?

Yes, pulled TB off motor, cleaned it with TB cleaner, replaced it, tried the relearn procedure. When I tap the throttle, it revs to around 2k and won’t come down. When I drive it, it wants to throttle up, so much that from a stop, it will shift into second gear and hit 25mph without even touching the throttle.

 

[HiHoeSilver]

Yes, pulled TB off motor, cleaned it with TB cleaner, replaced it, tried the relearn procedure. When I tap the throttle, it revs to around 2k and won’t come down. When I drive it, it wants to throttle up, so much that from a stop, it will shift into second gear and hit 25mph without even touching the throttle.

Which relearn did you try? Sometimes they just don't do it. You can either do a relearn with a tech 2 or just keep driving, it will learn eventually.

 

[Tonyrodz]

Sounds like the iac.